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Illinois State Rock

James St. John via Wikimedia Commons; Use permitted with attribution CC BY 2.0

Official State Rock of Illinois

Thanks to the efforts of students from Pleasantdale Middle School in Burr Ridge and Maplebrook Elementary School in Naperville, Illinois designated dolostone as the official state rock on June 6th, 2022 when Governor J.B. Pritzker signed House Bill 4261 into law.

Jennifer Lauermann, a Pleasantdale teacher, helped orchestrate the effort. When the students learned that Illinois didn't have a state rock, they went to work researching, visiting different museums, and interviewing area geology scholars. They created a website with a ballot and asked other students from across the state to vote for the best rock. Sandstone, Limestone, and Dolostone were on the ballot. Thousands of votes came in from across the state and Dolostone received more than 50% of the votes. The students then made a proposal to state lawmakers.

What is dolostone?

Dolostone, also known as dolomite and dolomite rock, is a sedimentary rock composed of the mineral dolomite. It is made up of calcium magnesium carbonate and is similar to limestone. Dolostone makes up the majority of the bedrock in Illinois and helps enrich the soil by providing rich nutrients.

What is dolostone used for?

Dolostone is a great building resource and is used in concrete and roads. In fact, 3,300 dolomite stones were used to build the Old State Capitol in Springfield. The stones were found in the quarry under what is now Lake Springfield. Dolostone was also used in some of the buildings constructed hundreds of years ago at the Lorado Taft Campus in Oregon, IL. Dolomite is also used for production of magnesium chemicals, such as Epsom salt, and is used as a magnesium supplement.